Touchscreens are well known in the art where the user communicates a desired action to a computer by touching a touchscreen in a specific location. The computer system displays graphics on the touchscreen that represent buttons. The user interfaces to the computer system by touching the touchscreen in a displayed button's sensing region, which is the area on the touchscreen that the computer system associates with the button. The computer system detects the user's touch, maps the touched location to a particular button, and performs appropriate functions based on the button that the user selected via the touch.
Touchscreens are advantageous in that they can eliminate the need for a keyboard or other input device in applications where a separate input device would be cumbersome, expensive, or susceptible to vandalism. Also, with a touchscreen the user is not forced to read instructions in one place and hunt elsewhere, such as on a keyboard, for keys to press. Instead, the instructions that the user reads and the buttons that the user touches are in the same proximity. This close proximity of instructions and buttons is more convenient and faster for the user and reduces the chance of incorrect button selection.
However, touchscreens suffer from the problem that the buttons on the touchscreen are two dimensional, and although the buttons are visually distinct from one another, they are not physically distinct from one another. Thus, while a user of a conventional keyboard can feel when a finger is straying over the edge of the intended key and onto an adjacent, unintended key, the user of a touchscreen cannot feel when a finger is straying over the edge of a button. These problems are exacerbated by the fact that the touchscreen has thickness, so while the button is projected onto the back of the touchscreen, the user touches it from the front. This screen thickness plus the parallax effect, causes different users to perceive the same button in potentially different places. For example, tall users standing to the right of the touchscreen will tend to perceive the button as being above and to the right of the actual button position, so they will tend to touch high and to the right of the button sensing region. Analogously, short users standing to the left of the touchscreen will tend to perceive the button as being below and to the left of the actual button position, so they will tend to touch low and to the left of the button sensing region.
The cumulative effect of these problems causes users to be unsure of whether or not they have touched the intended button, especially when the buttons are small and close together. In contrast, on a conventional keyboard, users can be reasonably confident that they have depressed the intended key because the key is three dimensional, moves downward when pressed, and is tactilely separate from adjacent keys.
The prior art touchscreens attempt to solve these problems by the computer system either displaying the button over a larger than desired area or utilizing a larger than desired button sensing region associated with the button. Both these solutions severely limited the density and orientation of displayed buttons on the touchscreen.
For the foregoing reasons, there is a need for a touchscreen that allows a high density of displayed buttons with accurate selection of buttons by users who are viewing the touchscreen from a variety of view angles.